Image forming apparatus

Abstract

An image forming apparatus includes: a body of the image forming apparatus; and a cartridge installable with respect to the body, wherein the cartridge includes a developer accommodating portion accommodating a developer; a developing portion supporting a developer holding member holding the developer thereon; and a shutter configured to be movable between an open position at which the shutter opens a communication port and a closed position at which the shutter closes the communication port. The body includes a detecting section detecting a state of the cartridge which changes as the cartridge is used, and a judging section judging whether or not a cartridge exchange timing for exchanging the cartridge has arrived, based on the state of the cartridge detected by the detecting section; and the shutter moves to the closed position under a condition that the judging section judges that the cartridge exchange timing has arrived.

What is claimed is: 
     
       1. An image forming apparatus comprising:
 a body of the image forming apparatus; and 
 a cartridge configured to be installed with respect to the body, 
 wherein the cartridge includes:
 a developer accommodating portion configured to accommodate a developer; 
 a developing portion configured to support a developer holding member configured to hold the developer thereon; and 
 a shutter configured to be movable between an open position at which the shutter opens a communication port allowing the developer accommodating portion to communicate with the developing portion, and a closed position at which the shutter closes the communication port, 
 
 the body includes:
 a detecting means for detecting a state of the cartridge which changes as the cartridge is used; 
 a shutter driving gear configured to drive the shutter, wherein the shutter is configured to move between the open position and an intermediate position, which is located between the open and closed positions, under a condition that an image forming operation is being executed; and 
 a controller connected to the detecting means, the controller being configured to judge whether a cartridge exchange timing for exchanging the cartridge has arrived, based on the state of the cartridge detected by the detecting means, and configured to control the shutter driving gear to move the shutter from the open position to the closed position when the controller judges that the cartridge exchanging timing has arrived. 
 
 
     
     
       2. The image forming apparatus according to  claim 1 ,
 wherein the detecting means is configured to detect the amount of the developer inside the developer accommodating portion, and 
 the controller is configured to judge whether the cartridge exchange timing has arrived based on the amount of the developer. 
 
     
     
       3. The image forming apparatus according to  claim 1 , wherein the developer accommodating portion is undetachable from the developing portion. 
     
     
       4. The image forming apparatus according to  claim 1 , wherein the developer accommodating portion includes a transporting member configured to transport the developer to the developing portion,
 the body includes a position sensor for detecting a position of the transporting member, and 
 the shutter is configured to move to the closed position under a condition that the position of the transporting member detected by the position sensor is a non-interfering position at which the transporting member does not interfere with the shutter. 
 
     
     
       5. The image forming apparatus according to  claim 1 , wherein the shutter is configured to pivot between the open position and the closed position. 
     
     
       6. The image forming apparatus according to  claim 1 , wherein the shutter is configured to be located at the open position in a case that the cartridge is unused. 
     
     
       7. The image forming apparatus according to  claim 1 , wherein the detecting means includes a developer empty sensor configured to detect an amount of the developer in the developer accommodating portion. 
     
     
       8. The image forming apparatus according to  claim 1 , wherein the detecting means is configured to detect the number of dots of a print pattern or the number of rotations of the developer holding member.